Publications by authors named "Jorge Burneo"

136 Publications

F-FDG PET-guided diffusion tractography reveals white matter abnormalities around the epileptic focus in medically refractory epilepsy: implications for epilepsy surgical evaluation.

Eur J Hybrid Imaging 2020 Jun 25;4(1):10. Epub 2020 Jun 25.

Lawson Imaging, Lawson Health Research Institute, 268 Grosvenor St., London, Ontario, N6A 4 V2, Canada.

Background: Hybrid PET/MRI can non-invasively improve localization and delineation of the epileptic focus (EF) prior to surgical resection in medically refractory epilepsy (MRE), especially when MRI is negative or equivocal. In this study, we developed a PET-guided diffusion tractography (PET/DTI) approach combining F-fluorodeoxyglucose PET (FDG-PET) and diffusion MRI to investigate white matter (WM) integrity in MRI-negative MRE patients and its potential impact on epilepsy surgical planning.

Methods: FDG-PET and diffusion MRI of 14 MRI-negative or equivocal MRE patients were used to retrospectively pilot the PET/DTI approach. We used asymmetry index (AI) mapping of FDG-PET to detect the EF as brain areas showing the largest decrease in FDG uptake between hemispheres. Seed-based WM fiber tracking was performed on DTI images with a seed location in WM 3 mm from the EF. Fiber tractography was repeated in the contralateral brain region (opposite to EF), which served as a control for this study. WM fibers were quantified by calculating the fiber count, mean fractional anisotropy (FA), mean fiber length, and mean cross-section of each fiber bundle. WM integrity was assessed through fiber visualization and by normalizing ipsilateral fiber measurements to contralateral fiber measurements. The added value of PET/DTI in clinical decision-making was evaluated by a senior neurologist.

Results: In over 60% of the patient cohort, AI mapping findings were concordant with clinical reports on seizure-onset localization and lateralization. Mean FA, fiber count, and mean fiber length were decreased in 14/14 (100%), 13/14 (93%), and 12/14 (86%) patients, respectively. PET/DTI improved diagnostic confidence in 10/14 (71%) patients and indicated that surgical candidacy be reassessed in 3/6 (50%) patients who had not undergone surgery.

Conclusions: We demonstrate here the utility of AI mapping in detecting the EF based on brain regions showing decreased FDG-PET activity and, when coupled with DTI, could be a powerful tool for detecting EF and assessing WM integrity in MRI-negative epilepsy. PET/DTI could be used to further enhance clinical decision-making in epilepsy surgery.
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http://dx.doi.org/10.1186/s41824-020-00079-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8218143PMC
June 2020

Epilepsy surgery in stroke-related epilepsy.

Seizure 2021 May 5;88:116-124. Epub 2021 Apr 5.

Epilepsy Program, Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, 339 Windermere Rd. London, Ontario, Canada, N6A 5A5; Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, 339 Windermere Rd. London, Ontario, Canada, N6A 5A5; Neuro-Epidemiology Unit, Schulich School of Medicine and Dentistry, Western University, 339 Windermere Rd. London, Ontario, Canada, N6A 5A5. Electronic address:

Purpose: To provide a descriptive analysis on the presurgical evaluation and surgical management of a cohort of patients with stroke related epilepsy (SRE).

Methods: We retrospectively examined the clinical characteristics, results of non-invasive and invasive presurgical evaluation, surgical management and outcome of consecutive patients with drug-resistant SRE in our institution from January 1, 2013 to January 1, 2020.

Results: Twenty-one of 420 patients (5%) who underwent intracranial EEG (iEEG), resective epilepsy surgery and/or vagus nerve stimulation (VNS) placement, had SRE. Of 13 patients who had iEEG, the ictal onset (IO) was exclusively within the stroke lesion in only one patient. In five patients the IO was extra-lesional and in the remaining seven patients it included the stroke lesion as well as extra-lesional structures. The IO included the mesial temporal region in 11 of the 13 patients (85%). The posterior margin of the stroke lesion was always involved. Five patients underwent surgery without iEEG. In total, 10 patients underwent resective surgery, four VNS placement and two had both corpus callosotomy and VNS placement. Of the patients who had resective surgery, nine were Engel I or II at last follow up.

Conclusion: We found that seizures in patients with drug resistant SRE were more frequently originated in the mesial temporal region than in the stroke lesion itself. Despite the complex epileptic network underlying drug-resistant SRE, a thorough presurgical assessment and adequate use of surgical options can lead to excellent surgical outcomes.
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http://dx.doi.org/10.1016/j.seizure.2021.04.002DOI Listing
May 2021

Vagus nerve stimulation does not alter brainstem nuclei morphology in patients with refractory epilepsy.

Epilepsy Behav 2021 05 7;118:107940. Epub 2021 Apr 7.

Department of Clinical Neurological Sciences, London Health Sciences Centre, Western University, London, Ontario, Canada; Department of Pathology and Lab Medicine, London Health Sciences Centre, Western University, London, Ontario, Canada. Electronic address:

Objective: To describe morphological characteristics of the brainstem nuclei in response to chronic vagus nerve stimulation (VNS) in patients with refractory epilepsy.

Background: VNS is a treatment option for individuals with medically refractory epilepsy. While treatment with VNS may achieve up to 50% seizure reduction and is protective against sudden unexpected death in epilepsy (SUDEP), its mechanism of action is not fully understood. Long-term structural and cellular changes in response to VNS have rarely been addressed in humans.

Methods: Four autopsy cases with history of chronic epilepsy treated with VNS (VNS+) and 4 age- and sex-matched chronic epilepsy-related death cases without VNS (VNS-) were included. Detailed clinical and postmortem data were obtained. Serial horizontal sections of the brainstem were prepared and stained with hematoxylin, eosin, and luxol fast blue (HE/LFB). Three regions of interest (ROIs) were delineated, including nucleus tractus solitarius (NTS), locus coeruleus (LC), and the rostral pontine group of raphe nuclei (rRN). Immunohistochemistry studies were performed using antibodies to GFAP, NeuN, HLA-DR, and IBA-1. Immunolabeling index was analyzed.

Results: Three of the 4 VNS+ patients and all 4 control (VNS-) patients died of SUDEP. There was no laterality difference in the NeuN, GFAP, HLA-DR and IBA-1 expression in LC and NTS of VNS+ patients. Similarly, there was no difference in the rRN, LC, and NTS between the VNS+ and VNS- groups.

Conclusion: This study represents the first histopathological study of the long-term effects of VNS therapy in the human brain. There was no difference observed in the neuronal cell number, degree of astrocytosis, and neuroinflammation in the main brainstem vagal afferent nuclei after prolonged VNS treatment in patients with refractory epilepsy.
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http://dx.doi.org/10.1016/j.yebeh.2021.107940DOI Listing
May 2021

Prevalence and incidence of epilepsy in Latin America and the Caribbean: A systematic review and meta-analysis of population-based studies.

Epilepsia 2021 Apr 2;62(4):984-996. Epub 2021 Mar 2.

Research Unit for the Generation and Synthesis of Evidence in Health, San Ignacio de Loyola University, Lima, Peru.

Objective: This study was undertaken to perform an updated systematic review and meta-analysis to estimate the pooled prevalence and incidence of epilepsy in Latin America and the Caribbean (LAC), describing trends over time, and exploring potential clinical and epidemiological factors explaining the heterogeneity in the region.

Methods: Observational studies assessing the incidence or prevalence of epilepsy in LAC countries up to March 2020 were systematically reviewed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Meta-analyses and cumulative analyses were performed using random-effects models. We assessed between-study heterogeneity with sensitivity, subgroup, and meta-regression analyses. Moreover, the quality of the included studies and the certainty of evidence were evaluated using the GRADE (grading of recommendation, assessment, development, and evaluation) approach.

Results: Overall, 40 studies (from 42 records) were included, 37 for prevalence analyses and six for incidence (312 387 inhabitants; 410 178 person-years). The lifetime prevalence was 14.09 per 1000 inhabitants (95% confidence interval [CI] = 11.72-16.67), for active epilepsy prevalence was 9.06 per 1000 individuals (95% CI = 6.94-11.44), and the incidence rate was 1.11 per 1000 person-years (95% CI = .65-1.70). These high estimates have been constant in the region since 1990. However, substantial statistical heterogeneity between studies and publication bias were found. The overall certainty of evidence was low. Methodological aspects (sample size) and countries' epidemiological characteristics such as access to sanitation services and child and adult mortality rates explained the high heterogeneity. Finally, the prevalence of epilepsy associated with neurocysticercosis (NCC) in the general population was high, and the proportion of NCC diagnosis among people living with epilepsy was 17.37%.

Significance: The epilepsy prevalence and incidence in LAC are higher than worldwide estimates, being constant since 1990 and strongly influenced by NCC. We identified high between-study heterogeneity and significant methodological limitations (e.g., heterogeneous definitions, lack of longitudinal studies). The region needs upgraded research using standardized definitions and diagnostic methods, and urgent action against preventable causes.
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http://dx.doi.org/10.1111/epi.16850DOI Listing
April 2021

An evaluation of the diagnostic equivalence of F-FDG-PET between hybrid PET/MRI and PET/CT in drug-resistant epilepsy: A pilot study.

Epilepsy Res 2021 May 16;172:106583. Epub 2021 Feb 16.

Lawson Imaging, Lawson Health Research Institute, London, ON, Canada; Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Department of Medical Imaging, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.

Objective: Hybrid PET/MRI may improve detection of seizure-onset zone (SOZ) in drug-resistant epilepsy (DRE), however, concerns over PET bias from MRI-based attenuation correction (MRAC) have limited clinical adoption of PET/MRI. This study evaluated the diagnostic equivalency and potential clinical value of PET/MRI against PET/CT in DRE.

Materials And Methods: MRI, FDG-PET and CT images (n = 18) were acquired using a hybrid PET/MRI and a CT scanner. To assess diagnostic equivalency, PET was reconstructed using MRAC (RESOLUTE) and CT-based attenuation correction (CTAC) to generate PET/MRI and PET/CT images, respectively. PET/MRI and PET/CT images were compared qualitatively through visual assessment and quantitatively through regional standardized uptake value (SUV) and z-score assessment. Diagnostic accuracy and sensitivity of PET/MRI and PET/CT for SOZ detection were calculated through comparison to reference standards (clinical hypothesis and histopathology, respectively).

Results: Inter-reader agreement in visual assessment of PET/MRI and PET/CT images was 78 % and 81 %, respectively. PET/MRI and PET/CT were strongly correlated in mean SUV (r = 0.99, p < 0.001) and z-scores (r = 0.92, p < 0.001) across all brain regions. MRAC SUV bias was <5% in most brain regions except the inferior temporal gyrus, temporal pole, and cerebellum. Diagnostic accuracy and sensitivity were similar between PET/MRI and PET/CT (87 % vs. 85 % and 83 % vs. 83 %, respectively).

Conclusion: We demonstrate here that PET/MRI with optimal MRAC can yield similar diagnostic performance as PET/CT. Nevertheless, further exploration of the potential added value of PET/MRI is necessary before clinical adoption of PET/MRI for epilepsy imaging.
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http://dx.doi.org/10.1016/j.eplepsyres.2021.106583DOI Listing
May 2021

All that glitters: Contribution of stereo-EEG in patients with lesional epilepsy.

Epilepsy Res 2021 Feb 2;170:106546. Epub 2021 Jan 2.

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Neuro-Epidemiology Unit, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. Electronic address:

Objective: To determine the contribution of stereo-EEG for localization purpose in patients with a visible lesion on MRI.

Background: Intracranial EEG is often used to localize the epileptogenic focus in patients with non-lesional focal epilepsy. Its role in cases where a lesion is visible on MRI can be even more complex and the relationship between the lesion and the seizure onset has rarely been addressed.

Methods: All consecutive patients between February 2013 and May 2018 who underwent stereo-EEG and had a lesion visible on MRI were included. We assessed the localization of the seizure onset and its relationship with the lesion. Clinical, radiological, and electrographic analyses were performed.

Results: Stereo-EEG revealed a seizure onset with either partial or no overlap with the lesion seen on MRI in 42 (56 %) of the 75 lesions included. Mesial temporal sclerosis was the only lesion type associated with an exclusively lesional seizure onset (p = 0.003).

Conclusion: Epilepsy surgery in MRI-positive cases should rely not only the results of lesions seen on MRI, which might be potentially misleading; SEEG is a gold standard method in these cases to define resective borders.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106546DOI Listing
February 2021

Letter by Fridman et al Regarding Article, "Incidence and Association of Reperfusion Therapies With Poststroke Seizures: a Systematic Review and Meta-Analysis".

Stroke 2021 01 28;52(1):e32-e33. Epub 2020 Dec 28.

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry (S.F., J.G.B., L.A.S.), Western University, London, ON, Canada.

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http://dx.doi.org/10.1161/STROKEAHA.120.032403DOI Listing
January 2021

Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy: A Canadian Experience.

Can J Neurol Sci 2021 Jul 16;48(4):469-478. Epub 2020 Oct 16.

Epilepsy Program, Department of Clinical Neurological Sciences, Schulich School of Medicine, Western University, London, Ontario, Canada.

Objective: To describe the experience with Anterior Nucleus of the Thalamus-Deep Brain Stimulation (ANT-DBS) for the treatment of epilepsy at a Canadian Center.

Methods: All patients who underwent ANT-DBS implantation between 2013 (first patient implanted at our center) and 2020 were included. These patients had therapy-resistant epilepsy (TRE), were not candidates for resective surgery, and failed vagus nerve stimulation (VNS) treatment. Baseline of monthly seizure frequency was calculated within 3 months prior to VNS placement. Monthly seizure frequency was assessed at different points along the timeline: 3 months before ANT-DBS implantation as well as 3, 6, 12, 24, 36, 48, 60, and 72 months after ANT-DBS device placement. At each time point, seizure frequency was compared to baseline.

Results: Six patients were implanted with ANT-DBS. Three (50%) patients had multifocal epilepsy, one (16.6%) had focal epilepsy, and two (33.4%) had combined generalized and focal epilepsy. Two patients with multifocal epilepsy experienced a seizure reduction >50% in the long-term follow-up. Three (50%) patients did not showed improvement: two with combined generalized and focal epilepsy and one with focal epilepsy. There were not surgical or device-related side effects. Two (33.3%) patients presented mild and transient headaches as a stimulation-related side effect.

Conclusion: ANT-DBS is an effective and safe treatment for focal TRE. Our experience suggests that patients with multifocal epilepsy due to regional lesion may benefit from ANT-DBS the most. Further investigations are required to determine optimal parameters of stimulation.
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http://dx.doi.org/10.1017/cjn.2020.230DOI Listing
July 2021

Epilepsy risk among survivors of intensive care unit hospitalization for sepsis.

Neurology 2020 10 4;95(16):e2271-e2279. Epub 2020 Sep 4.

From the Neuroepidemiology Research Unit (T.C.A., J.G.B.), Department of Clinical Neurological Sciences, Western University; ICES Western (B.N.A., L.R., S.Z.S., J.G.B.), London, Canada; and Department of Medicine (G.S.), Division of Neurology, University of Toronto, Canada.

Objective: To determine whether survivors of intensive care unit (ICU) hospitalizations with sepsis experience higher epilepsy risk than survivors of ICU hospitalizations without sepsis, and to identify sepsis survivors at highest risk.

Methods: We used linked, administrative health care databases to conduct a population-based, retrospective matched cohort study of adult Ontario residents discharged from an ICU between January 1, 2010, and December 31, 2015, identified using the Discharge Abstract Database. We used propensity scores to match patients who experienced sepsis during their index ICU hospitalization with up to 4 patients who did not experience sepsis. We applied marginal Cox proportional hazards regression to estimate the risk of epilepsy within 2 years following the index ICU hospitalization. Among sepsis survivors, Cox proportional hazards regression was used to identify factors associated with epilepsy.

Results: A total of 143,892 patients were included, 32,252 (22.4%) of whom were exposed. Sepsis survivors were at significantly higher epilepsy risk (hazard ratio [HR] 1.44, 95% confidence interval [CI] 1.15-1.80). The risk of epilepsy marginally decreased with increasing age (HR 0.97, 95% CI 0.96-0.99); patients with chronic kidney disease (HR 2.25, 95% CI 1.48-3.43) were at highest risk.

Conclusions: In this real-world analysis, sepsis survivors, particularly those who are younger and have chronic kidney disease, are at significantly higher epilepsy risk. These findings indicate that sepsis may be an unrecognized epilepsy risk factor.
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http://dx.doi.org/10.1212/WNL.0000000000010609DOI Listing
October 2020

Can we accurately lateralize the epileptogenic zone in patients who have seizure clusters? A study using stereo-electroencephalography.

Epilepsy Res 2020 10 23;166:106405. Epub 2020 Jun 23.

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Neuro-epidemiology Unit, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. Electronic address:

Objective: To determine if the ictal onset recorded with stereoelectroencephalography (SEEG) during clusters of seizures is reliable to identify the laterality of the epileptogenic zone.

Background: In the presurgical evaluation of patients with focal drug-resistant epilepsy, the presence of bilateral ictal onset is usually associated with a poor surgical outcome. It has been reported that the laterality of seizures can be influenced during seizure clusters, although this remains controversial. Most studies have addressed this issue using scalp EEG which could erroneously determine the laterality of the ictal onset.

Methods: We examined all consecutive patients who underwent SEEG with bilateral hemispheric coverage at our institution between January 2013 and September 2018. We assessed the presence of seizure clusters (clinical or subclinical), their laterality by SEEG and the surgical outcome of the patients. A descriptive clinical and electrographic analysis was performed.

Results: Of 143 patients who underwent SEEG recordings, we identified only six patients who had bilateral ictal onset that went on to resective surgery. In all six patients the discordant seizures occurred during a seizure cluster. Three of these patients were seizure free at last follow up.

Conclusion: Discordant seizures obtained during a seizure cluster may not necessarily mean that the patient has bilateral epilepsy, and therefore a poor post-surgical outcome. Seizure clusters may not reliably lateralize the epileptogenic zone.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106405DOI Listing
October 2020

Vagus nerve stimulation in patients with therapy-resistant generalized epilepsy.

Epilepsy Behav 2020 10 29;111:107253. Epub 2020 Jun 29.

Epilepsy Program, Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada; Neuroepidemiology Unit, Schulich School of Medicine, Western University, London, ON, Canada.

Background: For patients with generalized epilepsy who do not respond to antiseizure medications, the therapeutic options are limited. Vagus nerve stimulation (VNS) is a treatment mainly approved for therapy-resistant focal epilepsy. There is limited information on the use of VNS on generalized epilepsies, including Lennox-Gastaut Syndrome (LGS) and genetic generalized epilepsy (GGE).

Methods: We identified patients with a diagnosis of generalized epilepsy (including LGS and GGE), who underwent VNS implantation at the London Health Sciences Centre and Western University, London, Ontario, since this treatment became available in Canada in 1997 until July 2018. We assessed response to the treatment, including admissions to hospital and complications.

Results: A total of 46 patients were included in this study with a history of therapy-resistant generalized epilepsy. The mean age at implantation was 24 years (interquartile range [IQR] = 17.8-31 years), significantly younger in the LGS group (p = 0.02) and 50% (n = 23) were female. The most common etiologies were GGE in 37% (n = 17) and LGS in 63% (n = 29). Median follow-up since VNS implantation was 63 months (IQR: 31-112.8 months). Of the LGS group 41.7% (n = 12) of patients had an overall seizure reduction of 50% or more, and 64.7% (n = 11) in the GGE group without statistical significance between the groups. The best response in seizure reduction was seen in generalized tonic-clonic seizures, with a significant reduction in the GGE group (p = 0.043). There was a reduction of seizure-related hospital admissions from 91.3% (N = 42) preimplantation, to 43.5% (N = 20) postimplantation (p < 0.05). The frequency of side effects due to the stimulation was almost equal in both groups (62.1% in LGS and 64.7% in GGE).

Conclusions: Vagus nerve stimulation should be considered as a treatment in patients with therapy-resistant generalized epilepsy, especially in cases with GGE.
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http://dx.doi.org/10.1016/j.yebeh.2020.107253DOI Listing
October 2020

Stereoelectroencephalography Versus Subdural Strip Electrode Implantations: Feasibility, Complications, and Outcomes in 500 Intracranial Monitoring Cases for Drug-Resistant Epilepsy.

Neurosurgery 2020 07;87(1):E23-E30

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Canada.

Background: Both stereoelectroencephalography (SEEG) and subdural strip electrodes (SSE) are used for intracranial electroencephalographic recordings in the invasive investigation of patients with drug-resistant epilepsy.

Objective: To compare SEEG and SSE with respect to feasibility, complications, and outcome in this single-center study.

Methods: Patient characteristics, periprocedural parameters, complications, and outcome were acquired from a pro- and retrospectively managed databank to compare SEEG and SSE cases.

Results: A total of 500 intracranial electroencephalographic monitoring cases in 450 patients were analyzed (145 SEEG and 355 SSE). Both groups were of similar age, gender distribution, and duration of epilepsy. Implantation of each SEEG electrode took 13.9 ± 7.6 min (20 ± 12 min for each SSE; P < .01). Radiation exposure to the patient was 4.3 ± 7.7 s to a dose area product of 14.6 ± 27.9 rad*cm2 for SEEG and 9.4 ± 8.9 s with 21 ± 22.4 rad*cm2 for SSE (P < .01). There was no difference in the length of stay (12.2 ± 7.2 and 12 ± 6.3 d). The complication rate was low in both groups. No infections were seen in SEEG cases (2.3% after SSE). The rate of hemorrhage was 2.8% for SEEG and 1.4% for SSE. Surgical outcome was similar.

Conclusion: SEEG allows targeting deeply situated foci with a non-inferior safety profile to SSE and seizure outcome comparable to SSE.
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http://dx.doi.org/10.1093/neuros/nyaa112DOI Listing
July 2020

Seizure Freedom in Temporal Plus Epilepsy Surgery Following Stereo-Electroencephalography.

Can J Neurol Sci 2020 05;47(3):374-381

Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada.

Background: "Temporal plus" epilepsy (TPE) is a term that is used when the epileptogenic zone (EZ) extends beyond the boundaries of the temporal lobe. Stereotactic electroencephalography (SEEG) has been essential to identify additional EZs in adjacent structures that might be part of the temporal lobe/limbic network.

Objective: We present a small case series of temporal plus cases successfully identified by SEEG who were seizure-free after resective surgery.

Methods: We conducted a retrospective analysis of 156 patients who underwent SEEG in 5 years. Six cases had TPE and underwent anterior temporal lobectomy (ATL) with additional extra-temporal resections.

Results: Five cases had a focus on the right hemisphere and one on the left. Three cases were non-lesional and three were lesional. Mean follow-up time since surgery was 2.9 years (SD ± 1.8). Three patients had subdural electrodes investigation prior or in addition to SEEG. All patients underwent standard ATL and additional extra-temporal resections during the same procedure or at a later date. All patients were seizure-free at their last follow-up appointment (Engel Ia = 3; Engel Ib = 2; Engel Ic = 1). Pathology was nonspecific/gliosis for all six cases.

Conclusion: TPE might explain some of the failures in temporal lobe epilepsy surgery. We present a small case series of six patients in whom SEEG successfully identified this phenomenon and surgery proved effective.
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http://dx.doi.org/10.1017/cjn.2020.26DOI Listing
May 2020

Position Statement on the Use of Medical Cannabis for the Treatment of Epilepsy in Canada.

Can J Neurol Sci 2019 11;46(6):645-652

Cumming School of Medicine, University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada (JPA); UBC Department of Pediatrics, Division of Neurology, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada (CB); IWK Health Centre, Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada (PMB); Epilepsy Program, Department of Clinical Neurological Sciences and Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada (JGB); Alberta Children's Hospital, Departments of Neurosciences and Pharmacy, Calgary, Alberta, Canada (CSC); Division of Pediatric Neurology, Director of The Epilepsy Program, British Columbia's Children's Hospital, Vancouver, British Columbia, Canada (MBC); The Hospital for Sick Children, Department of Pharmacy, Ontario, Canada (MVTDG); Departments of Clinical Neurosciences and Radiology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada (PF); Past President CEA, Halifax, Nova Scotia, Canada (DF); Division of Pediatric Neurology, Department of Pediatrics, University of Saskatchewan, Cannabinoid Research Initiative of Saskatchewan, Saskatoon, Saskatchewan, Canada (RJH); Division of Neurology, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver General Hospital, Vancouver, British Columbia, Canada (MJ); Icahn School of Medicine at Mount Sinai, Department of Neurology and Population Health Science and Policy, New York, NY, USA (NJ); Nurse Practitioner Stollery Childrens Hospital, University of Alberta, Edmonton, Alberta, Canada (LLJ); Faculty of Medicine, Department of Neurosciences and Department of Social and Preventative Medicine, Université de Montréal, Clinician Researcher, Centre de Recherche du CHUM (CRCHUM), Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada (MRK); Department of Clinical Neurological Sciences, Division of Neurosurgery, Western University,Ontario, Canada (JCL); Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada (BM); Western University, London, Ontario, Canada (RSM); Department of Internal Medicine, Section of Neurology, University of Manitoba, Winnipeg, Manitoba, Canada (MCN); Centre Hospitalier de l'Université de Montréal Division of Neurology, Montréal, Quebec, Canada (DKN); Krembil Research Institute, University Health Network, Department of Medicine (Neurology), University of Toronto, Toronto Western Hospital, Toronto, Ontario, Canada (AYR); Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Section of Paediatric Neurology, Alberta Children's Hospital, Calgary, Alberta, Canada (JMR); The Hospital for Sick Children, University of Toronto, Department of Pediatrics, Toronto, Ontario, Canada (OCS); University of Saskatchewan, Saskatchewan Epilepsy Program, Division of Neurology, Department of Medicine Royal University Hospital, Saskatoon, Saskatchewan, Canada (JFTZ); The Hospital for Sick Children, Toronto, Ontario, Canada (LW); The Hospital for Sick Children, Division of Neurology, Toronto, Ontario, Canada (MMZ).

In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.
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http://dx.doi.org/10.1017/cjn.2019.282DOI Listing
November 2019

Relationship between déjà vu experiences and recognition-memory impairments in temporal-lobe epilepsy.

Memory 2019 Jul 24:1-11. Epub 2019 Jul 24.

a The Brain and Mind Institute and Department of Psychology, University of Western Ontario , London , Canada.

Déjà vu is characterised by feelings of familiarity and concurrent awareness that this familiarity is wrong. Previous neuropsychological research has linked déjà vu during seizures in individuals with unilateral temporal-lobe epilepsy (uTLE) to rhinal-cortex abnormalities, and to recognition-memory deficits that selectively affect familiarity assessment. Here, we examined whether bilateral TLE patients with déjà vu (bTLE) show a similar pattern of performance. Using two experimental tasks, we found that bTLE patients exhibit deficits not only for familiarity but also for recollection. Relative to uTLE, this broader impairment also involved hippocampal abnormalities. Our findings confirm rhinal-cortex contributions to the generation of false familiarity in déjà vu that parallel its contributions to familiarity on recognition-memory tasks. While they do not rule out a role for recollection in identifying this familiarity as wrong, the deficits observed in bTLE patients weigh against the notion that any such role is necessary for déjà vu to occur.
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http://dx.doi.org/10.1080/09658211.2019.1643891DOI Listing
July 2019

The risk of new-onset epilepsy and refractory epilepsy in older adult stroke survivors.

Neurology 2019 08 10;93(6):e568-e577. Epub 2019 Jul 10.

From the Epilepsy Program (J.G.B., T.C.A.), Department of Clinical Neurological Sciences, Western University; Institute for Clinical Evaluative Sciences Western (J.G.B., B.N.A., A.B., S.Z.S.), London; and Division of Neurology, Department of Medicine (G.S.), University of Toronto, Canada.

Objective: Our study objectives were to identify factors associated with new-onset epilepsy and refractory epilepsy among older adult stroke survivors and to evaluate the receipt of diagnostic care and mortality for participants who developed epilepsy.

Methods: We conducted a population-based, retrospective cohort study using linked, administrative health care databases. The Ontario Stroke Registry was used to identify patients 67 years and older who were hospitalized for a stroke at a designated stroke center in Ontario, Canada, between April 1, 2003, and March 31, 2009, and were previously free of epilepsy. Multivariable Fine-Gray hazard models were used to examine risk factors of epilepsy and refractory epilepsy, accounting for the competing risk of death.

Results: Among 19,138 older adults hospitalized for a stroke, 210 (1.1%) developed epilepsy and 27 (12.9%) became refractory to antiepileptic drugs. Within 1 year of epilepsy diagnosis, 24 (11.4%) patients were assessed with EEG and 19 (9.0%) with MRI. In multivariable analysis, younger age and thrombolysis receipt significantly increased epilepsy risk. Lesser stroke severity and anticoagulant medication receipt also significantly increased epilepsy risk; however, these effects decreased over time. Younger age and female sex were the only risk factors of refractory epilepsy. In the 5 years following epilepsy diagnosis, 97 (46.2%) participants died of any cause.

Conclusions: Older adult stroke survivors are less likely to develop epilepsy and pharmacologically refractory epilepsy. An estimated 86.6% of deaths among older adult stroke survivors with new-onset epilepsy are attributed to causes other than stroke or epilepsy.
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http://dx.doi.org/10.1212/WNL.0000000000007895DOI Listing
August 2019

The Predictive Value of Endpoint Quaking-Induced Conversion in Creutzfeldt-Jakob Disease.

Can J Neurol Sci 2019 09 3;46(5):595-598. Epub 2019 Jul 3.

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.

Creutzfeldt-Jakob disease (CJD) is a fatal neurological illness for which accurate diagnosis is paramount. Real-time quaking-induced conversion (RT-QuIC) is a prion-specific assay with high sensitivity and specificity for CJD. The Canadian endpoint quaking-induced conversion (EP-QuIC) test is similar, but unlike RT-QuIC there is little data regarding its diagnostic utility in clinical practice. In this exploratory predictive value analysis of EP-QuIC in CJD, the negative predictive value (NPV) and positive predictive value (PPV) was 100% and 83%, respectively, with one false-positive result identified. Re-testing this sample with an optimized EP-QuIC protocol eliminated this false-positive result, leading to a PPV of 100%.
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http://dx.doi.org/10.1017/cjn.2019.72DOI Listing
September 2019

Robot-Assisted Insular Depth Electrode Implantation Through Oblique Trajectories: 3-Dimensional Anatomical Nuances, Technique, Accuracy, and Safety.

Oper Neurosurg (Hagerstown) 2020 03;18(3):278-283

Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, Canada.

Background: The insula is a deep cortical structure that has renewed interest in epilepsy investigation. Invasive EEG recordings of this region have been challenging. Robot-assisted stereotactic electroencephalography has improved feasibility and safety of such procedures.

Objective: To describe technical nuances of three-dimensional (3D) oblique trajectories for insular robot-assisted depth electrode implantation.

Methods: Fifty patients who underwent robot-assisted depth electrode implantation between June 2017 and December 2018 were retrospectively analyzed. Insular electrodes were implanted through oblique, orthogonal, or parasagittal trajectories. Type of trajectories, accuracy, number of contacts within insular cortex, imaging, and complication rates were analyzed. Cadaveric and computerized tomography/magnetic resonance imaging 3D reconstructions were used to visualize insular anatomy and the technical implications of oblique trajectories.

Results: Forty-one patients (98 insular electrodes) were included. Thirty (73.2%) patients had unilateral insular coverage. Average insular electrodes per patient was 2.4. The mean number of contacts was 7.1 (SD ± 2.91) for all trajectories and 8.3 (SD ± 1.51) for oblique insular trajectories. The most frequently used was the oblique trajectory (85 electrodes). Mean entry point error was 1.5 mm (0.2-2.8) and target error was 2.4 mm (0.8-4.0), 2.0 mm (1.1-2.9) for anterior oblique and 2.8 mm (0.8-4.9) for posterior oblique trajectories. There were no complications related to insular electrodes.

Conclusion: Oblique trajectories are the preferred method for insular investigation at our institution, maximizing the number of contacts within insular cortex without traversing through sulci or major CSF fissures. Robot-assisted procedures are safe and efficient. 3D understanding of the insula's unique anatomical features can help the surgeon to improve targeting of this structure.
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http://dx.doi.org/10.1093/ons/opz154DOI Listing
March 2020

SUDEP: Let's talk about it.

Authors:
Jorge G Burneo

Neurology 2019 07 19;93(3):93-94. Epub 2019 Jun 19.

From the Epilepsy Program, Departments of Clinical Neurological Sciences and Epidemiology & Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Canada.

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http://dx.doi.org/10.1212/WNL.0000000000007771DOI Listing
July 2019

Diagnosing autoimmune limbic encephalitis.

CMAJ 2019 05;191(19):E529-E534

Departments of Clinical Neurological Sciences (Budhram, Nicolle, Burneo), and Medical Imaging (Leung), and the Neuroepidemiology Research Unit (Burneo), Western University, London, Ont.

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http://dx.doi.org/10.1503/cmaj.181548DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520067PMC
May 2019

Global Health and Epilepsy: Update and Future Directions.

Curr Neurol Neurosci Rep 2019 05 1;19(6):30. Epub 2019 May 1.

Nationwide Children's Hospital, Columbus, OH, USA.

Purpose Of Review: Efforts to improve epilepsy care outcomes in low- and middle-income countries (LMICs) are occurring through global health work. Despite an increase in these efforts, several barriers exist and a significant epilepsy treatment gap remains. This paper will review barriers to epilepsy care in LMICs and summarize recent published and unpublished data about global health projects which aimed to improve epilepsy care in these regions, focusing on work in the past 5 years.

Recent Findings: There are multiple recent and ongoing projects including clinical, research, education, and advocacy programs. We conclude that collaborative efforts are necessary in order to develop long-term and sustainable projects. The creation of a database and a formal method of communication between stakeholders can contribute to improving the efficiency and impact of global health efforts in epilepsy.
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http://dx.doi.org/10.1007/s11910-019-0947-6DOI Listing
May 2019

Population-Based Study of Risk of AKI with Levetiracetam.

Clin J Am Soc Nephrol 2019 01 11;14(1):17-26. Epub 2018 Dec 11.

Division of Nephrology, Department of Medicine, and Departments of

Background And Objectives: Regulatory agencies warn about the risk of AKI with levetiracetam use on the basis of information from case reports. We conducted this study to determine whether new levetiracetam use versus nonuse is associated with a higher risk of AKI.

Design, Setting, Participants, & Measurements: This was a population-based retrospective cohort study of adults with epilepsy in Ontario, Canada. Patients who received a new outpatient prescription for levetiracetam between January 1, 2004 and March 1, 2017 were matched to two nonusers on stage of CKD, recorded seizure in the prior 90 days, and logit of a propensity score for levetiracetam use. The primary outcome was a hospital encounter (emergency department visit or hospitalization) with AKI within 30 days of cohort entry. Secondary outcomes were AKI within 180 days and change in the concentration of serum creatinine. We assessed the primary outcome using health care diagnosis codes. We evaluated the change in the concentration of serum creatinine in a subpopulation with laboratory measurements.

Results: We matched 3980 levetiracetam users to 7960 nonusers (mean age 55 years, 51% women). Levetiracetam use was not significantly associated with a higher risk of AKI within 30 days (13 [0.33%] events in levetiracetam users and 21 [0.26%] events in nonusers [odds ratio, 1.24; 95% confidence interval, 0.62 to 2.47]). Similarly, there was no significant association with AKI within 180 days (odds ratio, 0.70; 95% confidence interval, 0.43 to 1.13). The change in the concentration of serum creatinine did not significantly differ between levetiracetam users and nonusers.

Conclusions: In this population-based study levetiracetam use was not associated with a higher risk of AKI.

Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_12_11_Yau_Podcast.mp3.
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http://dx.doi.org/10.2215/CJN.07490618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6364531PMC
January 2019

Epilepsy for primary health care: a cost-effective Latin American E-learning initiative.

Epileptic Disord 2018 Oct;20(5):386-395

Unidade de Pesquisa e Tratamento das Epilepsias, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.

A lack of neurologists in Latin America forces primary health care providers to manage epilepsy. With the main goal of improving diagnostic and therapeutic management of patients with epilepsy through training of physicians in the primary health care level, the International League Against Epilepsy Education Commission (2013-2017) created a low-cost, regional, virtual course. The course, set-up in Moodle platform, was structured in eight modules, each lasting for a week. Teaching was based on written didactic material, videos, and interactive discussions, both in Spanish and Portuguese. Topics included epidemiology, diagnosis, classification, treatment, prognosis, social issues, and epilepsy policies. Each course was limited to 50 participants and priority was given to general practitioners. Certification was given to those approving the final examination. Since 2015, five courses have been developed, involving 143 participants from 17 countries and 21 tutors. Of the participants, 61% worked in primary health care services. A total of 129 participants (90%) completed the course, and 110 submitted the final examination with an approval rate of 95%. From 85 participants completing the course evaluation, 98% would recommend the course to other colleagues, and 99% showed interest in taking other similar courses. High self-confidence for the management of patients with epilepsy increased from 21% at baseline to 73% after the course. The online course on epilepsy for primary care physicians in Latin America was shown to be a cost-effective course, with good retention and excellent approval rates. Our current challenges include periodic updating, complete self-sustainability, and exploring different strategies to reach our target audience more effectively.
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http://dx.doi.org/10.1684/epd.2018.0997DOI Listing
October 2018

Establishment of epilepsy surgery in Peru.

Neurology 2018 08;91(8):368-370

From the Epilepsy Program, Department of Clinical Neurological Sciences (D.A.S., J.G.B.), and Department of Anesthesia (M.F.A.), Schulich School of Medicine and Dentistry, Western University, London, Canada; Department of Epilepsy (C.M.V., J.C.D., W.Z.-L.), Instituto Nacional de Ciencias Neurologicas; and Departments of Neurology (A.B.) and Neurosurgery (E.B.), Hospital Nacional Edgardo Rebagliati Martins, Lima, Peru.

Epilepsy surgery is a well-established treatment for certain types of intractable epilepsy. While there is a relatively high number of epilepsy surgery centers in Canada and the United States, the same cannot be said about many other parts of the world, such as South America. Although there are notable exceptions, such as Brazil and Colombia, formal epilepsy surgery centers have been lacking in many South American countries, including Peru. Although sporadic cases have been performed in Peru, there was no formal epilepsy surgery center in the country as of 2011. Beginning in 2008, with the support of the Partnering Epilepsy Centers in America program of the North American Commission of the International League Against Epilepsy, the Epilepsy Program at Western University in London, Canada, was partnered with the Department of Epilepsy at the Instituto Nacional de Ciencias Neurologicas in Lima. This was the beginning of a long-term relationship that culminated in the establishment of the first 2 formal epilepsy surgery centers in Peru. The purpose of this communication is to briefly summarize the establishment of 2 independent epilepsy surgery programs in Peru and to document the methods with which this accomplishment was achieved.
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http://dx.doi.org/10.1212/WNL.0000000000006029DOI Listing
August 2018

Focal Epilepsy Secondary to Juxtacortical Lesions in Cerebral Autosomal Dominant Arteriopathy with Subacute Infarcts and Leukoencephalopathy.

Can J Neurol Sci 2018 07;45(4):462-463

1Department of Clinical Neurological Sciences,Western University,London,Ontario,Canada.

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http://dx.doi.org/10.1017/cjn.2018.29DOI Listing
July 2018

Clinical topography relationship in patients with parenchymal neurocysticercosis and seizures.

Epilepsy Res 2018 09 28;145:145-152. Epub 2018 Jun 28.

Center for Global Health - Tumbes, Universidad Peruana Cayetano Heredia, Lima, Peru; Cysticercosis Unit, Department of Transmissible Diseases, Instituto Nacional de Ciencias Neurologicas, Lima, Peru; Department of Microbiology, School of Sciences, Universidad Peruana Cayetano Heredia, Lima, Peru.

Objective: Discordances between imaging findings of parenchymal neurocysticercosis and seizure expression have been reported, and as such the possibility that neurocysticercosis and seizures may frequently coexist by chance has been raised. In this study, we evaluate the topographic relationship between seizure foci based on semiology and electroencephalography with the location of parenchymal neurocysticercotic lesions.

Methods: Seizure information, neuroimaging (computed tomography and magnetic resonance imaging [MRI]) and electroencephalographic data from three randomized clinical trials of individuals with parenchymal neurocysticercosis and focal seizures were analyzed. Blinded epileptologists defined a potential seizure onset zone and a symptomatogenic zone for each individual based on semiology. The topographic relationship between semiology, either lesion location or areas of perilesional edema on baseline MRI, and electroencephalographic abnormalities were assessed.

Results: Fifty-eight patients with one or two parenchymal neurocysticercotic lesions were included in this study. From them, 50 patients (86%; 95% CI, 75%-93%) showed a clinical-topography relationship with the potential seizure onset zone, and 44 (76%) also with the symptomatogenic zone. From the eight patients with no topographic relationship, five had focal seizures 30 days before or after the baseline MRI and showed perilesional edema. All of these five patients showed a clinical-topography relationship between such seizures and an area of perilesional edema, making a total of 55 patients (95%; 95% CI, 85%-99%) with clinical-topography relationship when perilesional edema is considered. Most patients with focal epileptiform discharges (7/8, 88%) had a topographic association between electroencephalographic focality, the potential seizure onset zone and a cysticercotic lesion.

Conclusion: Seizure semiology and focal epileptiform discharges are topographically related to neurocysticercotic lesions in most patients. These data strongly support seizure origin in the cortex surrounding these lesions.
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http://dx.doi.org/10.1016/j.eplepsyres.2018.06.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7063828PMC
September 2018

Intracranial Electroencephalographic Monitoring: From Subdural to Depth Electrodes.

Can J Neurol Sci 2018 05 12;45(3):336-338. Epub 2018 Apr 12.

Epilepsy Program,Department of Clinical Neurological Sciences,Schulich School of Medicine and Dentistry,Western University,London,Ontario,Canada.

At the London Health Sciences Centre Epilepsy Program, stereotactically implanted depth electrodes have largely replaced subdural electrodes in the presurgical investigation of patients with drug-resistant epilepsy over the past 4 years. The rationale for this paradigm shift was more experience with, and improved surgical techniques for, stereoelectroencephalography, a possible lower-risk profile for depth electrodes, better patient tolerability, shorter operative time, as well as increased recognition of potential surgical targets that are not accessible to subdural electrodes.
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http://dx.doi.org/10.1017/cjn.2018.4DOI Listing
May 2018

Novel connectivity map normalization procedure for improved quantitative investigation of structural thalamic connectivity in temporal lobe epilepsy patients.

J Magn Reson Imaging 2018 12 23;48(6):1529-1539. Epub 2018 Mar 23.

Imaging Research Laboratories, Robarts Research Institute - Western University, London, Ontario, Canada.

Background: Connectivity studies targeting the thalamus have revealed patterns of atrophy and deafferentiation in temporal lobe epilepsy (TLE). The thalamus can be parcellated using probabilistic tractography to demonstrate regions of cortical connectivity; however, sensitivity to smaller or less connected regions is low.

Purpose/hypothesis: To investigate thalamic structural connectivity in a wider range of cortical and limbic structures in TLE patients using a novel connectivity map normalization procedure.

Study Type: Retrospective.

Population/subjects: Patients (N = 23) with medication-resistant TLE and 34 healthy age-matched controls.

Field Strength/sequence: For T and diffusion weighting a spoiled gradient sequence was used (41 gradient directions [b = 1000]). For T mapping balanced steady-state free precession was used. Images were acquired at 3T.

Assessment: Probabilistic tractography and a novel normalization procedure allowed comparison of groups with respect to thalamic connected volume, quantitative MRI, and diffusion tensor imaging (DTI) metrics.

Statistical Tests: Independent samples t-test, Cohen's d, and Mann-Whitney tests.

Results: Following normalization, significant differences in thalamic connected volumes were found in left TLE vs. controls bilaterally within the posterior parahippocampal gyrus (L: P = 0.007, confidence interval [CI]: [173.306,1044.41], effect size [ES] = 1.072; R: P = 0.017, CI: [98.677,947.653], ES = 0.945), and contralaterally in the anterior temporal neocortex (P = 0.01, CI: (-2348.09, -333.719), ES = -1.021). This procedure revealed differences in thalamic connected volumes, where previously published procedures could not, and provided a basis for exploratory analysis of quantitative MRI and DTI metrics.

Data Conclusion: The novel connectivity map normalization scheme proposed here successfully allowed comparison between a wider range of cortical and limbic structures. Multiple volumetric and quantitative MRI and DTI-related differences between TLE patients and controls were revealed following normalization. With validation from a larger cohort, thalamo-temporal connection aberrancies may become useful biomarkers of disease states and probabilistic tractography as a procedure for identification of thalamic targets in modulatory therapies for TLE.

Level Of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1529-1539.
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http://dx.doi.org/10.1002/jmri.26013DOI Listing
December 2018

Gabapentin dose and the 30-day risk of altered mental status in older adults: A retrospective population-based study.

PLoS One 2018 14;13(3):e0193134. Epub 2018 Mar 14.

Institute for Clinical Evaluative Sciences, London, Ontario, Canada.

Gabapentin is an effective treatment for chronic neuropathic pain but may cause dizziness, drowsiness, and confusion in some older adults. The goal of this study was to assess the association between gabapentin dosing and adverse outcomes by obtaining estimates of the 30-day risk of hospitalization with altered mental status and mortality in older adults (mean age 76 years) in Ontario, Canada initiated on high dose (>600 mg/day; n = 34,159) compared to low dose (≤600 mg/day; n = 76,025) oral gabapentin in routine outpatient care. A population-based, retrospective cohort study assessing new gabapentin use between 2002 to 2014 was conducted. The primary outcome was 30-day hospitalization with an urgent head computed tomography (CT) scan in the absence of evidence of stroke (a proxy for altered mental status). The secondary outcome was 30-day all-cause mortality. The baseline characteristics measured in the two dose groups were similar. Initiation of a high versus low dose of gabapentin was associated with a higher risk of hospitalization with head CT scan (1.27% vs. 1.06%, absolute risk difference 0.21%, adjusted relative risk 1.29 [95% CI 1.14 to 1.46], number needed to treat 477) but not a statistically significant higher risk of mortality (1.25% vs. 1.16%, absolute risk difference of 0.09%, adjusted relative risk of 1.01 [95% CI 0.89 to 1.14]). Overall, the risk of being hospitalized with altered mental status after initiating gabapentin remains low, but may be reduced through the judicious use of gabapentin, use of the lowest dose to control pain, and vigilance for early signs of altered mental status.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193134PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5851574PMC
June 2018

Refractory Epilepsy: The Role of Positron Emission Tomography.

Can J Neurol Sci 2018 01;45(1):30-34

1Department of Clinical Neurological Sciences,London Health Sciences Centre,London,Ontario,Canada.

Rationale: Presurgical localization of the epileptogenic focus is critical to successful surgery. Traditionally, localization of the epileptogenic focus depends on seizure semiology, scalp video-electroencephalography (vEEG), magnetic resonance imaging (MRI), neuropsychological assessment, and, when needed, intracranial EEG (iEEG). We aimed to explore the role of positron emission tomography (PET) in the presurgical evaluation of patients with refractory epilepsy.

Methods: A retrospective review was conducted on patients from London Health Sciences Centre (London, Ontario) with refractory epilepsy who underwent PET from September of 2011 to April of 2016. The accuracy of epileptogenic focus localization was compared between different investigative modalities (MRI, vEEG, iEEG, PET), and the outcomes were documented, including seizure freedom after surgical resection, improvement of seizure frequency, guidance for further investigations, and exclusion of patients from further evaluation. Patients who underwent surgery were followed up at 3 months and onward.

Results: We identified 62 patients with refractory epilepsy who underwent PET. The mean age was 34 years (range=20-68). A total of 36 had concordant PET and vEEG findings: 6 had surgical resection and either became seizure-free (29.4%) or had improvement in seizure frequency (5.9%) at 3 months; 11 had surgical resection and either became seizure-free (29.4%) or had improvement in seizure frequency (35.3%) at 3 months, but required iEEG for final verification.

Conclusions: PET has an important role in presurgical evaluation of patients with refractory epilepsy. It may allow resection of the epileptogenic focus without the need for iEEG, guiding intracranial electrode placement for further localization of the epileptogenic focus, or exclusion of patients from further evaluation.
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http://dx.doi.org/10.1017/cjn.2017.244DOI Listing
January 2018
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